The following invention relates to brushless electromechanical machines for converting electrical energy into mechanical motion and vice-versa. More specifically, the invention relates to an electric motor/generator having self-starting capabilities, high torque and increased efficiency.
Electric motors employing brushes are characterized by low efficiency and require elaborate starter mechanisms. Recently, a type of brushless motor has been developed which employs an electromagnet having a stator comprised of a plurality of toroidal pole pieces. The pole pieces each have a narrow gap to permit the passage of a disk shaped rotor. The rotor includes a plurality of permanent magnets spaced about the periphery of the disk. As the permanent magnets pass through the gap in the stator poles, the permanent magnets are attracted and repulsed to move the rotor. With appropriate switching circuitry, this combination can be made to function as a brushless electric motor. An example of such construction is shown in Porter U.S. Pat. No. 5,179,307.
A problem with the motor of the '307 patent is that the motor requires some type of auxiliary starter mechanism in order to begin rotation of the disk. Additionally, this motor cannot easily reverse its direction.
What is needed in the art are rotary and linear electromagnetic machines that provide higher torque and power density for a given size and weight, lower losses for higher efficiency, and do not require an auxiliary starter mechanism, that is, are self starting.